dotnet/wpf · error · InvalidOperationException

SR.LocalValueEnumerationOutOfBounds

Error message

SR.LocalValueEnumerationOutOfBounds

What it means

LocalValueEnumerator.Current throws InvalidOperationException(SR.LocalValueEnumerationOutOfBounds) when the enumerator has moved past the last element (MoveNext returned false and iteration ended). This implements the documented IEnumerator.Current behavior. Reading Current after enumeration has completed is a caller sequencing error.

Solutions

1. Only access Current when MoveNext() returns true.
2. Replace manual enumerator code with a foreach loop.
3. Reset the enumerator via Reset() if you need to iterate again (and then MoveNext first).
4. Capture values inside the loop instead of dereferencing Current afterwards.

Example fix

// before
var e = obj.GetLocalValueEnumerator();
while (e.MoveNext()) { /* ... */ }
var last = e.Current; // throws: past end
// after
var e = obj.GetLocalValueEnumerator();
LocalValueEntry last = null;
while (e.MoveNext()) { last = e.Current; }

// read Current only inside: while (e.MoveNext()) { use e.Current; }

null

try { var cur = e.Current; }
catch (InvalidOperationException) { /* enumeration already finished */ }

When it happens

Trigger: Continuing to read Current after MoveNext() has returned false; calling Current again after the loop finished; reusing a spent enumerator.

Common situations: do/while loops that read Current before checking MoveNext's return value; caching the enumerator and dereferencing Current later; custom collection processors that run one iteration too many.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• InvalidOperationException
• SR.Enumerator_CollectionChanged
• SR.Enumerator_NotStarted
• SR.Enumerator_NotStarted
• SR.Enumerator_NotStarted

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/0325d6300cd881a4. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/LocalValueEnumerator.cs:76

        }
        
        /// <summary>
        ///     Get current entry
        /// </summary>
        public LocalValueEntry Current
        {
            get
            {
                if(_index == -1 )
                {
                    // IEnumerator.Current is documented to throw this exception
                    throw new InvalidOperationException(SR.LocalValueEnumerationReset);
                }

                if(_index >= Count )
                {
                    // IEnumerator.Current is documented to throw this exception
                    throw new InvalidOperationException(SR.LocalValueEnumerationOutOfBounds);
                }
                
                return _snapshot[_index];
            }
        }

        /// <summary>
        ///     Get current entry (object reference based)
        /// </summary>
        object IEnumerator.Current
        {
            get { return Current; }
        }

        /// <summary>
        ///     Move to the next item in the enumerator
        /// </summary>
        /// <returns>Success of the method</returns>

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